The sea anemone, Exaiptasia diaphana , is a model of coral-dinoflagellate (Symbiodiniaceae) symbiosis. However, little is known of its potential to form symbiosis with Cladocopium —a key Indo-Pacific algal symbiont of scleractinian corals, nor the host nutritional consequences of such an association. Aposymbiotic anemones were inoculated with homologous algal symbionts, Breviolum minutum , and seven heterologous strains of Cladocopium C1 acro (wild-type and heat-evolved) under ambient conditions. Despite lower initial algal cell density, Cladocopium C1 acro -anemeones achieved similar cell densities as B. minutum -anemones by week 77. Wild-type and heat-evolved Cladocopium C1 acro showed similar colonization patterns. Targeted LC-MS-based metabolomics revealed that almost all significantly different metabolites in the host and Symbiodiniaceae fractions were due to differences between Cladocopium C1 acro and B. minutum , with little difference between heat-evolved and wild-type Cladocopium C1 acro at week 9. The algal fraction of Cladocopium C1 acro -anemones was enriched in metabolites related to nitrogen storage, while the host fraction of B. minutum -anemones was enriched in sugar-related metabolites. Compared to B. minutum , Cladocopium C1 acro is likely slightly less nutritionally beneficial to the host under ambient conditions, but more capable of maintaining its own growth when host nitrogen supply is limited. Our findings demonstrate the value of E. diaphana to study experimentally evolved Cladocopium .
An accurate representation of physical and biological processes is crucial to resolve larval dispersal pathways and characterize connectivity of coral reef ecosystems. We investigate how hydrodynamic forcings drive larval retention rates during the bi‐annual mass coral spawning of the coral genus Acropora within a coral reef atoll (Mermaid Reef), located off northwestern Australia. By analyzing hydrodynamic conditions during 41 yr of historical spring and autumn coral spawning events, we identify typical and extreme hydrodynamic forcing conditions. Particle tracking using the output from a fine‐scale coupled wave‐flow hydrodynamic model forced with typical hydrodynamic conditions during coral spawning, revealed a mean transport of larvae eastward across the atoll. Transport was mainly driven by a combination of wave and tidal currents, where the residual tidal flow and unidirectional wave flow increased the net export of particles, and the oscillatory tidal (non‐residual) flow reduced the net export of particles from the reef. Importantly, however, numerical simulations forced with extreme hydrodynamic conditions generated by episodic tropical cyclones (11 out of 41 yr) showed large deviations from the typical eastward flow during autumn spawning, generating different connectivity pathways within the reef. Considering the substantial time larvae can be retained within reef systems, overlooking fine‐scale hydrodynamic processes may greatly overestimate larval transport distances between adjacent coral reef atolls. As a result, we emphasize the need to consider fine‐scale hydrodynamic processes within regional connectivity predictions, which is generally not considered yet critical to understand the capacity of reefs to recover following disturbances.
Many coral reef fishes display remarkable genetic and phenotypic variation across their geographic ranges. Understanding how historical and contemporary processes have shaped these patterns remains a focal question in evolutionary biology, since they reveal how diversity is generated and how it may respond to future environmental change. Here we compare the population genomics and demographic histories of a commercially and ecologically important coral reef fish, the common coral grouper (Plectropomus leopardus [Lacépède 1802]), across two adjoining regions (the Great Barrier Reef; GBR, and the Coral Sea, Australia) spanning approximately 14 degrees of latitude and 9 degrees of longitude. We analysed 4,548 single nucleotide polymorphism (SNP) markers across 11 sites and show that genetic connectivity between regions is low, despite their relative proximity (~ 100 km) and an absence of any obvious geographic barrier. Inferred demographic histories using 10,479 markers suggest that the Coral Sea population was founded by a small number of GBR individuals and that divergence occurred ~ 190 kya under a model of isolation with asymmetric migration. We detected population expansions in both regions, but estimates of contemporary effective population sizes were approximately 50 % smaller in Coral Sea sites, which also had lower genetic diversity. Our results suggest that P. leopardus in the Coral Sea have experienced a long period of isolation that precedes the recent glacial period (~ 10 – 120 kya) and may be vulnerable to localised disturbances due to their relative reliance on local larval replenishment. While it is difficult to determine the underlying events that led to the divergence of Coral Sea and GBR lineages, we show that even geographically proximate populations of a widely dispersed coral reef fish can have vastly different evolutionary histories.
To survive in nutrient-poor waters corals rely on a symbiotic association with intracellular microalgae. However, increased sea temperatures cause algal loss—known as coral bleaching—often followed by coral death. Some of the most compelling evidence in support of the ‘oxidative stress theory of coral bleaching’ comes from studies that exposed corals, cultures of their algal endosymbionts, or the coral model Exaiptasia diaphana to exogenous antioxidants during thermal stress. Here, we replicate these experiments using E. diaphana with the addition of the antioxidants ascorbate + catalase, catechin, or mannitol under ambient and elevated temperatures along with an antioxidant-free control. In the absence of exogenous antioxidants, E. diaphana exposed to elevated temperatures bleached with no change in reactive oxygen species (ROS) levels associated with their microalgal cells. Ascorbate + catalase and mannitol treatments rescued the anemones from bleaching, although microalgal ROS levels increased in these antioxidant treatments under elevated temperature conditions. While bleaching was not associated with changes in net ROS for the intracellular algal symbionts, it is evident from our findings that excess ROS is connected to the bleaching phenotype as exogenous antioxidants were successful in mitigating the effects of thermal stress in cnidarians. This understanding may assist applied research that aims to reduce the impact of climate change on coral reefs.
On the Great Barrier Reef (GBR), persistent changes to reef communities have begun to be documented, and on inshore reefs these shifts may favour the prolifera- tion of macroalgae. Critical to understanding changes to reef community structure in response to anthropogenic impacts is developing effective methods to accurately document the abundance of different reef organisms. Effective monitor- ing must be time and cost efficient, replicable, and able to sufficiently and accurately detect disturbances to allow development of strategies to mitigate their impacts. Tradi- tional techniques to document coral reef communities (i.e. photo-quadrats, benthic intercept transects) rely on planar views, which tend to either over- or under-represent canopy- forming organisms. As canopy-forming organisms are likely to be affected by anthropogenic influences (corals negatively, algae positively), it is essential for monitoring programs to implement methods sufficient to document changes to the vertical dimension of coral reefs. Here we build on previous work to document the canopy effect in coral-dominated ecosystems and propose a new survey approach suitable for implementation in algal-dominated systems. A vertically stratified transect, modified from a traditional point intercept transect, captures benthic and canopy-forming members of reef communities and provides information on three-dimensional complexity. To test the capability of the new method to detect changes in vertical reef structure, seaweed was removed from experimental quadrats and monitoring techniques were applied before and after four months of regrowth. A stratified method more accurately captured the three-dimensional change resulting from algal canopy growth, while resolving the over-and under-representation of algal biomass in two traditional techniques. We propose that a stratified transect method improves abundance estimates of canopy-forming organisms whilst maintaining data compatibility with traditional methods.
The ‘evolutionary arms race’ between predator and prey is responsible for many physiological, morphological, and behavioural adaptations and some of the most compelling examples relate to the generation and detection of visual signals. Better understanding of adaptations can arise from approaching predator-prey dynamics from the point of view of the animals themselves, such as through animal-borne cameras. As we learn more about an animal's visual system, we can take this further and analyse visual scenes through their eyes. In this study video cameras mounted on tiger sharks were used to analyse motion cues of sea turtles using two-dimensional motion detector (2DMD) models. Sharks were also equipped with tri-axial motion-sensors to compare visual motion cues to behaviour, using the behavioural metrics of overall dynamic body acceleration (ODBA), path tortuosity, tailbeat frequency and tailbeat acceleration signal amplitude. When comparing the behaviours of sharks in the minute before and after interactions with sea turtles, we found lower ODBA of sharks associated with sea turtles that produced greater visual motion cues. These turtles also invoked swimming by sharks that was more tortuous than when no turtle was encountered. Together, these behaviours suggest that tiger sharks may potentially stalking turtles that produced greater motion cues. Many sea turtles did not stand out from the background motion suggesting they remain motionless as a form of camouflage. This study provides insights into the use of visual cues in prey identification by tiger sharks and the camouflage strategies used by sea turtles to avoid predation.
Coral bleaching, the result of loss of endosymbiotic dinoflagellates, as well as post-bleaching recovery can be exacerbated or mitigated by a range of local factors such as depth, turbidity, and natural or artificial shading providing protection for corals during thermal anomalies. On many reefs, losses in coral cover coincide with increases in upright macroalgae growth. Such shifts in benthic communities are generally viewed as negative, whereby macroalgae can outcompete corals for space, and affect adult coral health and fitness. However, the canopy provided by upright macroalgae could reduce solar irradiance and provide refuge for understorey corals during heat events, decreasing coral bleaching and subsequent mortality. To test this hypothesis, this study manually removed macroalgae from experimental plots on a macroalgae-dominated fringing reef at Magnetic Island in the central inshore region of the Great Barrier Reef, comparing the subsequent bleaching during and recovery following a severe heat stress event. In March 2020, sea surface temperature at Magnetic Island reached 31.4 °C, leading to bleaching. Surveys of coral communities undertaken at the peak of accumulated severe heat stress (DHW of 9.3 °C-weeks) in control and macroalgae removal plots showed that, averaged across coral morphological groups, there was no overall difference in bleaching prevalence in algal-removal and control plots (21.1% and 20.8% of the community bleached; respectively). However, bleaching prevalence varied within morphological groups, with massive morphology corals demonstrating higher probability of bleaching in removal plots compared to controls (0.26 and 0.09, respectively). Bleaching severity (i.e. percent of the colony tissue bleached) was consistent across control and removal plots (83.2% and 80.4% of colony area, respectively, averaged across morphologies), with branching corals demonstrating the lowest severity. Surveys were repeated in July after heat stress had dissipated, with coral communities in algal-removal plots displaying greater recovery than controls (i.e. 86.1% and 75.6% healthy, respectively, model estimated mean averaged across morphologies). Encrusting corals in control plots were the slowest to recover. We conclude that macroalgae provided limited refuge for branching and encrusting corals at the height of the thermal event, likely due to the severity of the accumulated heat stress, while massive corals enjoyed some degree of protection from the canopy. Greater recovery of coral communities in removal plots may potentially be explained by reduced competition with adjacent macroalgae. This study provides important insights into the interactions between these two dominant benthic groups and supports previous work finding macroalgae inhibits coral recovery after severe bleaching events.
Algal turfs trap and retain particulates, however, little is known about the relationship between particulate accumulation and taxonomic composition of algal turfs. We investigated how particulate mass related to algal turf structure (length and density) and community composition (taxonomic and functional) on two disparate reefs. Particulate mass was positively related to algal turf length. By contrast, the relationship between particulate mass and turf density was more complex and followed a negative parabolic shape; density increased with particulate mass before stabilising and then declining. Community analyses showed taxonomic, but not functional group compositions differed significantly between reefs and with increasing particulate mass. Our results suggest high loads of particulates accumulated in algal turfs are related to a longer, lower density turf structure, typified by filamentous forms such as Cladophora. Changes in algal turf structure and composition could have a variety of bottom-up influences on coral reef ecosystems.
Machine-assisted object detection and classification of fish species from Baited Remote Underwater Video Station (BRUVS) surveys using deep learning algorithms presents an opportunity for optimising analysis time and rapid reporting of marine ecosystem statuses. Training object detection algorithms for BRUVS analysis presents significant challenges: the model requires training datasets with bounding boxes already applied identifying the location of all fish individuals in a scene, and it requires training datasets identifying species with labels. In both cases, substantial volumes of data are required and this is currently a manual, labour-intensive process, resulting in a paucity of the labelled data currently required for training object detection models for species detection. Here, we present a “machine-assisted” approach for i) a generalised model to automate the application of bounding boxes to any underwater environment containing fish and ii) fish detection and classification to species identification level, up to 12 target species. A catch-all “fish” classification is applied to fish individuals that remain unidentified due to a lack of available training and validation data. Machine-assisted bounding box annotation was shown to detect and label fish on out-of-sample datasets with a recall between 0.70 and 0.89 and automated labelling of 12 targeted species with an F1 score of 0.79. On average, 12% of fish were given a bounding box with species labels and 88% of fish were located and given a fish label and identified for manual labelling. Taking a combined, machine-assisted approach presents a significant advancement towards the applied use of deep learning for fish species detection in fish analysis and workflows and has potential for future fish ecologist uptake if integrated into video analysis software. Manual labelling and classification effort is still required, and a community effort to address the limitation presented by a severe paucity of training data would improve automation accuracy and encourage increased uptake.
Monitoring programs are fundamental to understanding the state and trend of aquatic ecosystems. Sampling designs are a crucial component of monitoring programs and ensure that measurements evaluate progress toward clearly stated management objectives, which provides a mechanism for adaptive management. Here, we use a well-established marine monitoring program for inshore water quality in the Great Barrier Reef (GBR), Australia to investigate whether a sampling re-design has increased the program’s capacity to meet its primary objectives. Specifically, we use bootstrap resampling to assess the change in statistical power to detect temporal water quality trends in a 15-year inshore marine water quality data set that includes data from both before and after the sampling re-design. We perform a comprehensive power analysis for six water quality analytes at four separate study areas in the GBR Marine Park and find that the sampling re-design (i) increased power to detect trends in 23 of the 24 analyte-study area combinations, and (ii) resulted in an average increase in power of 34% to detect increasing or decreasing trends in water quality analytes. This increase in power is attributed more to the addition of sampling locations than increasing the sampling rate. Therefore, the sampling re-design has substantially increased the capacity of the program to detect temporal trends in inshore marine water quality. Further improvements in sampling design need to focus on the program’s capability to reliably detect trends within realistic timeframes where inshore improvements to water quality can be expected to occur.
The evolution of very large body size requires a ubiquitous and abundant source of food. In marine environments the largest animals such as whale sharks are secondary consumers that filter feed on nekton, which is plentiful, although patchy. Consequently, feeding in coastal environments requires cost‐efficient foraging that focuses on oceanographic features that aggregate both nektonic prey and marine debris such as floating macroalgae. Consumption of this algae could present an energetic challenge for these animals, unless some component can be digested. Here, we use a multi‐technique approach involving amino acid compound‐specific stable isotope analysis (CSIA) and fatty acid analysis to determine the trophic level of whale sharks and to identify likely items in the diet. CSIA analyses showed that the species has a trophic level consistent with omnivory. Fatty acid profiles of whale shark tissues, faeces and potential prey items suggest that the floating macroalgae, Sargassum, and its associated epibionts is a significant source of food. Although this overcomes the energetic challenge of consumption of floating algae, this mode of feeding and the need to focus on oceanographic features that aggregate prey also increases the threat to the species posed by pollutants such as plastic.
Genomic studies are uncovering extensive cryptic diversity within reef‐building corals, suggesting that evolutionarily and ecologically relevant diversity is highly underestimated in the very organisms that structure coral reefs. Furthermore, endosymbiotic algae within coral host species can confer adaptive responses to environmental stress and may represent additional axes of coral genetic variation that are not constrained by taxonomic divergence of the cnidarian host. Here, we examine genetic variation in a common and widespread, reef‐building coral, Acropora tenuis, and its associated endosymbiotic algae along the entire expanse of the Great Barrier Reef (GBR). We use SNPs derived from genome‐wide sequencing to characterise the cnidarian coral host and organelles from zooxanthellate endosymbionts (genus Cladocopium). We discover three distinct and sympatric genetic clusters of coral hosts, whose distributions appear associated with latitude and inshore‐offshore reef position. Demographic modelling suggests that the divergence history of the three distinct host taxa ranges from 0.5 – 1.5 million years ago, preceding the GBR’s formation, and has been characterised by low to moderate ongoing inter‐taxon gene flow, consistent with occasional hybridisation and introgression typifying coral evolution. Despite this differentiation in the cnidarian host, A. tenuis taxa share a common symbiont pool, dominated by the genus Cladocopium (Clade C). Cladocopium plastid diversity is not strongly associated with host identity but varies with reef location relative to shore: inshore colonies contain lower symbiont diversity on average but have greater differences between colonies as compared to symbiont communities from offshore colonies. Spatial genetic patterns of symbiont communities could reflect local selective pressures maintaining coral holobiont differentiation across an inshore‐offshore environmental gradient. The strong influence of environment (but not host identity) on symbiont community composition supports the notion that symbiont community composition responds to habitat, and may assist in the adaptation of corals to future environmental change.
Indonesian coral reefs are under pressure from illegal, unregulated and unreported fishing, the use of destructive fishing practices, land-based pollution, coastal development and climate change. Marine protected areas (MPAs) are necessary to allow habitat recovery and fish stock replenishment. Through the United States Agency for International Development Sustainable Ecosystems Advanced Project (2016–2021), Indonesia worked to improve fisheries productivity and sustainable livelihoods within the three provinces of Maluku, North Maluku and West Papua, where 13 new coral reef MPAs were designed for multiple use, with a zoning system to support biodiversity conservation and sustainable fisheries. At the time of writing in mid-2021, regulations to prohibit fishing within the no-take areas (NTAs) were not yet implemented. This paper presents baseline and trends in percent coral cover and reef fish density and biomass in the MPAs. In 2020, overall coral cover had increased from 42% to 45% across all MPAs. The average target fish biomass across all NTAs had declined from 1709 ( ± 176 SE) kg per hectare in 2017 to 884 ( ± 76 SE) kg per hectare in 2020, representing a significant decline of about 48%. Large and significant declines in many target fish families across multiple MPAs are reflective of unsustainable levels of exploitation. It is evident that management plans need to be implemented with adequate enforcement and stakeholder engagement to stem the decline of target species and to secure livelihoods for local fishing communities.
Organismal metabolic rates (MRs) are the basis of energy and nutrient fluxes through ecosystems. In the marine realm, fishes are some of the most prominent consumers. However, their metabolic demand in the wild (field MR [FMR]) is poorly documented, because it is challenging to measure directly. Here, we introduce a novel approach to estimating the component of FMR associated with voluntary activity (i.e., the field active MR [AMRfield]). Our approach combines laboratory‐based respirometry, swimming speeds, and field‐based stereo‐video systems to estimate the activity of individuals. We exemplify our approach by focusing on six coral reef fish species, for which we quantified standard MR and maximum MR (SMR and MMR, respectively) in the laboratory, and body sizes and swimming speeds in the field. Based on the relationships between MR, body size, and swimming speeds, we estimate that the activity scope (i.e., the ratio between AMRfield and SMR) varies from 1.2 to 3.2 across species and body sizes. Furthermore, we illustrate that the scaling exponent for AMRfield varies across species and can substantially exceed the widely assumed value of 0.75 for SMR. Finally, by scaling organismal AMRfield estimates to the assemblage level, we show the potential effect of this variability on community metabolic demand. Our approach may improve our ability to estimate elemental fluxes mediated by a critically important group of aquatic animals through a non‐destructive, widely applicable technique. We know little about the metabolic demand of fishes in the wild. We propose a new approach to estimate active field metabolic rates by combining laboratory‐based respirometry and field‐based stereo‐video systems.
We present a description of the large-scale physical oceanography of the southeast Indian Ocean to provide context for this special issue, revisiting 110°E as part of the Second International Indian Ocean Expedition. Full watermass properties and circulation are introduced based on the hydrographic observations, as well as underway systems and satellite sea surface height measurements. The 110°E line provides a window into the global meridional overturning circulation and the shallow overturning of the Indian Ocean. Measurements of change along this line provide valuable insight into the pulse of the climate system. The full depth hydrographic transects of 1963 and 2019 will provide invaluable calibration points for investigation of climate variability using the diverse observations that contribute to the Indian and global ocean observing systems.
Oil pollution remains a prominent local hazard to coral reefs, but the sensitivity of some coral life stages to oil exposure remains unstudied. Exposure to ultraviolet radiation (UVR), ubiquitous on coral reefs, may significantly increase oil toxicity towards these critical habitat-forming taxa. Here we present the first data on the sensitivity of two distinct post-settlement life stages of the model coral species Acropora millepora to a heavy fuel oil (HFO) water accommodated fraction (WAF) in the absence and presence of UVR. Assessment of lethal and sublethal endpoints indicates that both 1-week-old and 2-month-old recruits (1-wo and 2-mo) were negatively affected by chronic exposures to HFO (7 and 14 days, respectively). Relative growth (1-wo and 2-mo recruits) and survival (1-wo recruits) at end of exposure were the most sensitive endpoints in the absence of UVR, with no effect concentrations (NEC) of 34.3, 5.7 and 29.3 μg L⁻¹ total aromatic hydrocarbons (TAH; ∑39 monocyclic- and polycyclic aromatic hydrocarbons), respectively. On average, UVR increased the negative effects by 10% for affected endpoints, and latent effects of exposure were evident for relative growth and symbiont uptake of recruits. Other sublethal endpoints, including maximum quantum yield and tissue colour score, were unaffected by chronic HFO exposure. A comparison of putative species-specific sensitivity constants for these ecologically relevant endpoints, indicates A. millepora recruits may be as sensitive as the most sensitive species currently included in oil toxicity databases. While the low intensity UVR only significantly increased the negative effects of the oil for one endpoint, the majority of endpoints showed trends towards increased toxicity in the presence of UVR. Therefore, the data presented here further support the standard incorporation of UVR in oil toxicity testing for tropical corals.
Intensifying anthropogenic stressors have contributed to declines in reef-building corals in many regions. These disturbances result in reduced live coral cover, impacting key population-level processes such as coral larval settlement and recruitment that are essential for reef recovery. Reef restoration efforts that rely on enhanced larval supply provide a pathway for the recovery of degraded reefs. However, corals at very early life stages experience high post-settlement mortality bottlenecks, which impede stock-recruitment processes. Overcoming these bottlenecks is a high priority goal in coral restoration. Some coral larvae are known to be capable of gaining exogenous nutrients. Therefore, we hypothesised that the capacity to access exogenous nutrients may confer advantages to larval survival, settlement and post-settlement success. The present study aimed to quantify the effect of larval feeding on coral larvae settlement and early post-settlement survival. We completed an ex-situ experiment using aposymbiotic larvae of two broadcast spawning reef-building coral species - Acropora tenuis and Acropora millepora. Larvae were randomly assigned to either fed or unfed treatment groups for each species. Fed larvae received homogenised Artemia once a day, for three days. Results show that for both species, feeding significantly increased larval settlement. Feeding A. millepora larvae more than doubled mean settlement (13.0 ± 1.17 SE vs 31.4 ± 2.88 SE; p <0.001). Similarly, feeding A. tenuis larvae increased mean settlement from 18.2 ( ± 1.85 SE) to 29.9 ( ± 2.22 SE; p <0.001). Larval feeding had an immediate positive effect on spat survival, such that A. millepora and A. tenuis spat from fed treatments had increased survival three days post-settlement (89.5% ± 3.75 SE vs 70.6% ± 2.59 SE, p <0.001; 88.8% ± 2.21 SE vs 71.4% ± 3.80 SE, p <0.001, respectively). Therefore, enhancing settlement and early post-settlement survival by feeding larvae homogenised Artemia has the potential to improve the effectiveness of larval rearing protocols and coral restoration efforts.
Conservation of marine ecosystems has been highlighted as a priority to ensure a sustainable future. Effective management requires data collection over large spatio-temporal scales, readily accessible and integrated information from monitoring, and tools to support decision-making. However, there are many roadblocks to achieving adequate and timely information on both the effectiveness, and long-term success of conservation efforts, including limited funding, inadequate sampling, and data processing bottlenecks. These factors can result in ineffective, or even detrimental, management decisions in already impacted ecosystems. An automated approach facilitated by artificial intelligence (AI) provides conservation managers with a toolkit that can help alleviate a number of these issues by reducing the monitoring bottlenecks and long-term costs of monitoring. Automating the collection, transfer, and processing of data provides managers access to greater information, thereby facilitating timely and effective management. Incorporating automation and big data availability into a decision support system with a user-friendly interface also enables effective adaptive management. We summarise the current state of artificial intelligence and automation techniques used in marine science and use examples in other disciplines to identify existing and potentially transferable methods that can enable automated monitoring and improve predictive modelling capabilities to support decision making. We also discuss emerging technologies that are likely to be useful as research in computer science and associated technologies continues to develop and become more accessible. Our perspective highlights the potential of AI and big data analytics for supporting decision-making, but also points to important knowledge gaps in multiple areas of the automation processes. These current challenges should be prioritised in conservation research to move toward implementing AI and automation in conservation management for a more informed understanding of impacted ecosystems to result in successful outcomes for conservation managers. We conclude that the current research and emphasis on automated and AI assisted tools in several scientific disciplines may mean the future of monitoring and management in marine science is facilitated and improved by the implementation of automation.
No-take marine reserves are often located in remote locations far away from human activity, limiting perceived impact on extractive users but also reducing their use for investigating impacts of fishing. This study aimed to establish a benchmark in the distribution of fished species across the Ningaloo Marine Park – Commonwealth (NMP-Commonwealth), and adjacent comparable habitats within the Ningaloo Marine Park - State (NMP-State), in Western Australia to test if there was evidence of an effect of recreational fishing, as no commercial fishing is allowed within either marine park. We also examined whether the remote location of the newly established (2018) No-take Zone (NTZ), in NMP-Commonwealth, limits its use for studying the effects of fishing. Throughout the NMP-Commonwealth and NMP-State, where recreational fishing is permitted, we expected the abundance of recreationally fished fish species to increase with increasing distance to the nearest boat ramp, as a proxy of recreational fishing effort. Conversely, we did not expect the abundance of non-fished species and overall species richness to vary in response to the proxy for human activity. Distance to the nearest boat ramp was found to be a strong predictor of fished species abundance, indicating that the effect of recreational fishing can be detected across the NMP-Commonwealth. The effect of the NTZ on fished species abundance was weakly positive, but this difference across the NTZ is expected to increase over time. Habitat composition predictors were only found to influence species richness and non-fished species abundance. This study suggests a clear footprint of recreational fishing across the NMP-Commonwealth and as a result the new NTZ, despite its remote location, can act as a control in future studies of recreational fishing effects.
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